U.S. patent number 5,038,569 [Application Number 07/510,262] was granted by the patent office on 1991-08-13 for thermoelectric converter.
This patent grant is currently assigned to Nippondenso Co., Ltd.. Invention is credited to Kenichi Fujiwara, Kazutoshi Nishizawa, Hideo Ohta, Yuichi Shirota, Yoshitaka Tomatsu, Kenji Yamada.
United States Patent |
5,038,569 |
Shirota , et al. |
August 13, 1991 |
Thermoelectric converter
Abstract
A thermoelectric converter has a N-type thermoelectric element,
a P-type thermoelectric element, an endothermic electrode and a
radiative electrode. One surface of the N-type thermoelectric
element is attached to one surface of the endothermic electrode and
the other surface is attached to one surface of the radiative
electrode. One surface of the P-type thermoelectric element is
attached to the other surface of the radiative electrode and the
other surface is attached to the other endothermic electrode.
Inventors: |
Shirota; Yuichi (Anjo,
JP), Nishizawa; Kazutoshi (Toyoake, JP),
Tomatsu; Yoshitaka (Nagoya, JP), Fujiwara;
Kenichi (Kariya, JP), Ohta; Hideo (Toyohashi,
JP), Yamada; Kenji (Chiryu, JP) |
Assignee: |
Nippondenso Co., Ltd. (Kariya,
JP)
|
Family
ID: |
27461985 |
Appl.
No.: |
07/510,262 |
Filed: |
April 17, 1990 |
Foreign Application Priority Data
|
|
|
|
|
Apr 17, 1989 [JP] |
|
|
1-96888 |
Aug 4, 1989 [JP] |
|
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1-203581 |
Feb 27, 1990 [JP] |
|
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2-47044 |
Apr 5, 1990 [JP] |
|
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2-90965 |
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Current U.S.
Class: |
62/3.2;
62/3.7 |
Current CPC
Class: |
F25B
21/02 (20130101); H01L 35/30 (20130101) |
Current International
Class: |
F25B
21/02 (20060101); H01L 35/28 (20060101); H01L
35/30 (20060101); F25B 021/02 () |
Field of
Search: |
;62/3.1,3.2,3.3,3.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: King; Lloyd L.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
What is claimed is:
1. A thermoelectric converter comprising:
a thermoelectric converting portion having an N-type thermoelectric
element, a first electrode, and a P-type thermoelectric element and
a second electrode which are stacked sequentially in the order
stated in a way such that said first electrode completely separates
said N-type thermoelectric element from said P-type thermoelectric
element, being in contact with and separating adjacent and opposite
surfaces of said N-type and P-type thermoelectric elements,
respectively;
one of said electrodes being an endothermic electrode and the other
being a radiative electrode;
endothermic means thermally connected to the endothermic electrode
for absorbing heat; and
radiative means thermally connected to the radiative electrode for
radiating heat.
2. A thermoelectric converter comprising:
a first electrode having one surface;
an N-type thermoelectric element having first and second opposite
surfaces, the first surface being coupled to said one surface of
said first electrode;
a second electrode having first and second opposite surfaces, the
first of which is coupled to said second surface of the N-type
thermoelectric element;
a P-type thermoelectric element which has one surface coupled to
the said second surface of the second electrode in a location
adjacent a coupled location of said N-type thermoelectric element
on said second electrode;
one of said electrodes being an endothermic electrode and the other
being a radiative electrode;
endothermic means thermally connected to the endothermic electrode
for absorbing heat; and
radiative means thermally connected to the radiative electrode for
radiating heat.
3. A thermoelectric converter comprising:
two rows of thermoelectric converting portions, each thermoelectric
converting portion having an N-type thermoelectric element, a first
electrode, a P-type thermoelectric element and a second electrode
which are stacked sequentially from one side to another side of
each row in the order stated, in a way such that said first
electrode completely separates said N-type thermoelectric element
from said P-type thermoelectric element, being contact with and
separating adjacent and opposite surfaces of said N-type and P-type
thermoelectric elements, one of said electrodes being an
endothermic electrode and the other being a radiative
electrode;
connecting means for connecting electrically one row of
thermoelectric converting portions with the other row of
thermoelectric converting portions at the same sides thereof;
endothermic means thermally connected to the endothermic electrode
for absorbing heat; and
radiative means thermally connected to the radiative electrode for
radiating heat.
4. A thermoelectric converter as in claim 1, 2 or 3, wherein a
plurality of the P-type thermoelectric elements are attached to
each endothermic electrode and an adjacent radiative electrode and
a plurality of the N-type thermoelectric elements are attached to
each radiative electrode and adjacent endothermic electrode.
5. A thermoelectric converter as in claim 1, 2 or 3, wherein the
endothermic means and the radiative means comprise louvers which
are formed on the endothermic electrode and the radiative
electrode.
6. A thermoelectric converter as in claim 1, 2 or 3, wherein the
endothermic means and the radiative means comprise corrugated fins
which are attached to the endothermic electrode and the radiative
electrode.
7. A thermoelectric converter as in claim 1, 2 or 3, wherein the
endothermic means and the radiative means comprise heat pipes which
are thermally connected to the endothermic electrode and the
radiative electrode respectively.
8. A thermoelectric converter of claim 1, 2 or 3 further comprising
an insulator which insulates the radiative means from the
endothermic means thermally and electrically.
9. A thermoelectric converter as in claim 1, 2 or 3 wherein said
electrodes are U-shaped.
10. A thermoelectric converter as in claim 1, 2 or 3 wherein said
electrodes are fan shaped.
11. A thermoelectric converter as in claim 1, 2 or 3 wherein each
of said electrodes comprises a pair of parallel plates.
12. A thermoelectric converter as in claim 1, 2 or 3 wherein said
electrodes are comb shaped.
13. A thermoelectric converter as in claim 1, 2 or 3 wherein said
electrodes are zig-zag shaped.
14. A thermoelectric converter as in claim 1, 2 or 3 wherein each
said electrode comprises a plurality of fingers adjacent ones of
which are bent outward in opposite directions.
15. A thermoelectric converter as in claim 1, 2 or 3 wherein said
electrodes are oriented at an acute angle relative to a direction
of alignment of said thermoelectric elements.
16. A thermoelectric converter as in claim 4 wherein said
electrodes have a slit in a center portion thereof for compensating
for mechanical expansion and contraction.
17. A thermoelectric converter as in claim 4 wherein said
electrodes have two slits in a center portion thereof for
compensating for mechanical expansion and contraction.
18. A thermoelectric converter as in claim 3, wherein two N-type
thermoelectric elements are connected to one surface of the first
electrode and two P-type thermoelectric elements are connected to
the other surface of the first electrode.
19. A method of exchanging heat comprising the steps of:
making a thermoelectric converting portion having an N-type
thermoelectric element, a first electrode, a P-type thermoelectric
element and a second electrode which are stacked sequentially in
the order stated, so that said first electrode is completely
between said N-type thermoelectric element and said P-type
thermoelectric element and in contact with adjacent surfaces of
said N and P-type and thermoelectric elements, one of said
electrodes being an endothermic electrode and the other being a
radiative electrode;
connecting an endothermic means to said endothermic electrode;
applying current to said thermoelectric converting portion in a
direction of stacking thereof, so that said endothermic means
absorbs heat and the radiative electrode radiates heat.
20. A thermoelectric converter as in claim 1, 2, or 3, wherein said
N-type and P-type thermoelectric elements and said first and second
electrodes are disposed with respect to a direction of stacking
thereof.
21. A thermoelectric converter as in claim 1, 2 or 3, wherein said
N-type and P-type thermoelectric elements and said first and second
electrodes are inclined and non perpendicular with respect to a
direction of stacking thereof.
22. A thermoelectric converter as in claim 2 further
comprising:
a third electrode having a first surface connected to a second
surface, opposite to said first surface, of said P-type
thermoelectric element;
a second N-type thermoelectric element connected to a second
surface of said third electrode opposite to said first surface;
wherein a plane which would be formed in a direction of resultant
current flow passing through at least a portion of all of said
thermoelectric elements.
23. A thermoelectric converter as in claim 2 further
comprising:
a second P-type thermoelectric element connected to a second
surface, opposite to said first surface, of said first
electrode.
24. A thermoelectric converter as in claim 1, wherein said first
electrode is a flat electrode having a width defined between
surfaces to which said N-type thermoelectric element and said
P-type thermoelectric element are coupled, and said thermoelectric
converting portion is stacked such that resultant current flow is
in a direction of stacking and in a direction of said width of said
first electrode.
25. A thermoelectric converter as in claim 2, wherein said second
electrode is a flat electrode having a width defined between said
first and second surfaces, and said thermoelectric converting
portion is stacked such that resultant current flow is in a
direction of stacking and in a direction of said width of said
second electrode.
26. A thermoelectric converter as in claim 3, wherein each said
first electrode is a flat electrode having a width defined between
surfaces to which said N-type thermoelectric element and said
P-type thermoelectric element are coupled, and said thermoelectric
converting portion is stacked such that resultant current flow is
in a direction of stacking and in a direction of said width of said
each first electrode.
27. A method as in claim 19, wherein said first electrode is a flat
electrode having a width defined between surfaces to which said
N-type thermoelectric element and said P-type thermoelectric
element are coupled, and said thermoelectric converting portion is
stacked such said applying current step forms resultant current
flow in a direction of stacking and in a direction of said width of
said first electrode.
28. A thermoelectric converter as in claims 1 or 3, wherein said
first electrode is in contact with an entirety of one face of both
of said N and P thermoelectric elements.
29. A thermoelectric converter as in claim 2, wherein said second
electrode is in contact with an entirety of one face of both of
said N and P thermoelectric elements.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a thermoelectric converter which
could be compact and has high nonconductivity.
A conventional thermoelectric converter which is shown in Japanese
unexamined Patent (Kokai) No. 53-99796, as shown in FIG. 27, has a
thermoelectric converting portion 80, an endothermic heat exchanger
81 and a radiative heat exchanger 82 for radiating and absorbing
heat by the Peltier effect. The thermoelectric converting portion
80 comprises a plurality of P-type thermoelectric elements (P-type
semiconductor) 1p' and N-type thermoelectric elements (N-type
semiconductor) 1n' which are disposed one after the other, a
plurality of endothermic electrodes 83 which connect an end of the
P-type thermoelectric element 1p' with an end of the N-type
thermoelectric element 1n' and a plurality of radiative electrodes
84 which connect the other end of the P-type thermoelectric element
1p' with the other end of the N-type thermoelectric element
1n'.
The endothermic heat exchanger 81 includes a insulating plate 85
which is thermally connected to the endothermic electrodes 83, and
an endothermic metal plate 86 which is thermally connected to the
insulating plate 85.
The radiative heat exchanger 82 includes an insulating plate 87
which is thermally connected to the radiative electrode 84, and a
radiative metal plate 88 which is thermally connected to the
insulating plate 87.
The radiative electrode 84a is connected to a negative pole of an
electric supply (not shown) and the radiative electrode 84b is
connected to a positive pole. The endothermic electrodes 83 absorb
heat, and then the endothermic metal plate 86 is cooled. The
radiative electrodes 84 radiate heat, and then the radiative metal
plate 88 is heated.
In the conventional device described above, the insulating plates
85 and 87 are disposed between the electrodes 83 and 84 and the
metal plates 86 and 88 in order to prevent short-circuits between
the adjacent endothermic electrodes 83 and the adjacent radiative
electrodes 84. The insulating plates 85, 87 decrease the efficiency
of radiating and absorbing heat due to the thermal resistance of
the insulating plates 85, 87 and the contacting thermal resistance
between the endothermic metal plate 86 and the insulating plate 85,
the insulating plate 85 and the endothermic electrode 83, the
radiative electrode 84 and the insulating plate 87, the insulating
plate 87 and the radiative plate 88.
Since an electric current flows through each of electrodes 83, 84,
Joule heat is generated due to the electric resistance of
electrodes 83, 84 and the efficiency of cooling is decreased. The
cross sectional area of the electrodes 83, 84 across the direction
of the electric current is small and the length of the electrodes
83, 84 along the direction of the electric current is long, so the
electric resistance becomes larger and the Joule heat
increases.
If the length of the electrodes 83, 84 becomes shorter, a short
circuit might be caused between adjacent electrodes 83 and/or
between adjacent electrodes 84. For instance, when the length of
the endothermic electrode 83 becomes shorter, two of the radiative
electrodes 84 come closer. In other words, enough distance between
adjacent electrodes is required to avoid a short circuit, so that
it is hard to make the device compact.
If adjacent electrodes short circuit, the thermoelectric elements
could not radiate or absorb heat.
SUMMARY OF THE INVENTION
An object of this invention is to provide a compact thermoelectric
converter without causing short circuiting, but instead causing
nonconductivity, between adjacent radiative electrodes and between
adjacent endothermic electrodes.
The thermoelectric converter of the present invention comprises a
thermoelectric converting portion, an endothermic heat exchanging
portion which is disposed on a side of the thermoelectric
converting portion and a radiative heat exchanging portion which is
disposed on the other side of the thermoelectric converting
portion. The thermoelectric converting portion has N-type
thermoelectric elements, endothermic electrodes, P-type
thermoelectric elements and radiative electrodes which are built up
sequentially. The endothermic heat exchanging portions are
thermally connected to the endothermic electrodes and the radiative
heat exchanging portions are thermally connected to the radiative
electrodes.
A direct voltage is applied to both ends of the thermoelectric
converting portion and a direct current flows sequentially through
the N-type thermoelectric elements, the endothermic electrodes, the
P-type thermoelectric elements and the radiative electrodes. Due to
the Peltier effect, each of the endothermic electrodes becomes
lower in temperature at and around the surfaces contacting the
thermoelectric elements, and the endothermic heat exchangers absorb
the heat. Each of radiative electrodes becomes higher in
temperature at and around the surfaces contacting the
thermoelectric elements and the radiative heat exchangers radiate
the heat.
There are always a radiative or endothermic electrode and a P-type
or N-type thermoelectric element between two of adjacent
endothermic electrodes. The nonconductivities between adjacent
endothermic electrodes and adjacent radiative electrodes are kept
high even if the P-type and the N-type thermoelectric elements
become smaller.
Other objects, advantages and complete structures of the invention
will become more apparent from the following description and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of the first embodiment of the
thermoelectric converter with center portions taken away,
FIG. 2 is a perspective view of a part of the first embodiment,
FIGS. 3, 4, 5 and 6 are cross sectional views of different types of
the first embodiment,
FIG. 7 is a cross sectional view of the second embodiment of the
thermoelectric converter,
FIG. 8 is a cross sectional view taken along the line 8--8 of FIG.
7,
FIG. 9 is a partially schematic, cross sectional view of an air
conditioner for an automobile to which the second embodiment is
applied.
FIG. 10 is a partially schematic, cross sectional view of an
air-conditioner for an automobile to which the third embodiment is
applied,
FIG. 11 is a front view of the third embodiment with parts broken
away,
FIG. 12 is a perspective view showing a thermoelectric converting
portion of the third embodiment,
FIG. 13 is a perspective view showing a modification of a
thermoelectric converting portion of the third embodiment.
FIG. 14 is a front view of the thermoelectric converting portion
shown in FIG. 13,
FIG. 15 is a perspective view showing a further modification of a
thermoelectric converting portion of the third embodiment,
FIG. 16 is a perspective view of the fourth embodiment of the
thermoelectric converter with center portions taken away,
FIG. 17 is a side view of the fourth embodiment,
FIG. 18 is a cross sectional view taken along the line 18--18 of
FIG. 17,
FIG. 19 is a cross sectional view taken along the line 19--19 of
FIG. 17,
FIG. 20 is a cross sectional view taken along the line 20--20 of
FIG. 17 with central portions taken away,
FIG. 21 is a perspective view of a holding member used for the
fourth embodiment with central portions taken away,
FIG. 22 is a front view of another modification of the fourth
embodiment,
FIG. 23 is a cross sectional view taken along the line 23--23 of
FIG. 22,
FIG. 24 is a perspective view of parts of the fifth embodiment,
FIG. 25 is a plain view of the fifth embodiment,
FIG. 26 is a cross sectional view taken along the line 26--26 of
FIG. 25,
FIG. 27 is a cross sectional view of a conventional thermoelectric
converter,
FIG. 28 is a cross sectional view of the first embodiment,
FIG. 29 is a perspective view of a corrugated fin shown in FIG.
28,
FIGS. 30 and 31 are front views of the other modification of the
fourth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Various embodiments of the present invention are described
hereinafter. In each embodiment, parts which have the same function
have the same numeral.
THE FIRST EMBODIMENT
The first embodiment of the present invention is described in FIG.
1.
The thermoelectric converter has a thermoelectric converting
portion 1. The thermoelectric converting portion 1 comprises N-type
thermoelectric elements 1n, endothermic electrodes 11, P-type
thermoelectric elements 1p and radiative electrodes 12. The N-type
thermoelectric element 1n, the endothermic electrodes 11, the
P-type thermoelectric elements 1p and the radiative electrodes 12
are built up sequentially in this order. The thermoelectric
converting portion 1 has plural groups of those elements and
electrodes. The N-type thermoelectric elements 1n and the P-type
thermoelectric elements 1p are connected to the endothermic
electrodes 11 and the radiative electrodes 12 by soldering. A
positive electrode 13 and a negative electrode 14 are respectively
connected to opposite ends of the thermoelectric converting portion
1.
N-type semiconductors and P-type semiconductors made from
bismuth-tellurium material are respectively used as N-type
thermoelectric elements 1n and P-type thermoelectric elements 1p
and have exemplary dimensions of 3mm.times.3mm.times.1.3mm.
The endothermic electrodes 11 and the radiative electrodes 12 are
rectangular shape of 3 cm.times.2 cm.times.1 mm for example, and
are made of copper alloy. The N-type thermoelectric elements 1n are
connected to a surface of the endothermic electrodes 11 and the
radiative electrodes 12 by soldering. The P-type thermoelectric
elements 1p are connected to the other surface of the endothermic
electrodes 11 and the radiative electrodes 12 by soldering. The
endothermic electrodes 11 and the radiative electrodes 12 have a
heat exchanging portion wherein louvers 22 are formed, as shown in
FIG. 2. The louvers 22 include a plurality of strips which are
parallel to the longitudinal axis of the electrodes 11, 12. The
louvers 22 of the endothermic electrode 11 is not shown in FIG. 2.
The adjacent louvers 22 extend in opposite directions to each other
as shown in FIG. 1. The electrodes 11, 12 are disposed
perpendicularly to the built-up or longitudinal direction of the
thermoelectric elements 1p, 1n in such a manner that the
endothermic electrodes 11 and the radiative electrodes 12 extend in
opposite directions to each other.
This thermoelectric converter is assembled in a way described
hereinafter. One surface of the endothermic electrode 11 and one
surface of the N-type thermoelectric element 1n are soldered to
each other, and one surface of the radiative electrode 12 and one
surface of the P-type thermoelectric element lp are soldered to
each other. Then, the other surface of endothermic electrode 11 and
the other surface of the P-type thermoelectric element 1p are
soldered to each other, and the other surface of the radiative
electrode 12 and the other surface of the N-type thermoelectric
element 1n are soldered to each other. Finally, the positive
electrode 13 and the negative electrode 14 are soldered at opposite
ends of the thermoelectric converting portion 1.
The operation of the thermoelectric converter is described
hereinafter.
A nonconductive fluid to be cooled flows through the louvers 22 of
the endothermic electrode 11 and a nonconductive coolant flows
through the louvers 22 of the radiative electrode 12. An insulating
member (not shown) is disposed at the thermoelectric converting
portion to prevent the fluid to be cooled and the coolant from
mixing physically and thermally with each other.
When direct current is applied between the positive electrode 13
and the negative electrode 14, the surfaces of the endothermic
electrodes 11 which contact the P-type thermoelectric element 1p
and also the N-type thermoelectric element 1n and the vicinity
around those contacting surfaces become cooler due to the Peltier
effect, and then the endothermic electrodes 11 absorb heat from the
fluid to be cooled through the louvers 22. The surfaces of the
radiative electrodes 12 which contact both of the thermoelectric
elements 1p, 1n and the vicinity around those contacting surfaces
become hotter due to the Peltier effect, and then the radiative
electrodes 12 radiate the heat toward the coolant through the
louvers 22. The heat absorbed from the fluid to be cooled and the
Joule heat generated at the P-type and N-type thermoelectric
elements 1p and 1n are transferred to the coolant.
According to the thermoelectric converter of the first
embodiment:
(A) Since the endothermic electrodes 11 of the heat absorbing
portion (the endothermic heat exchanger in the present invention)
and the radiative electrodes 11 of the heat radiating portion (the
radiative heat exchanger in the present invention), the heat is
easily transferred from the thermoelectric converting portion 1 to
the heat radiative portion and from the heat absorbing portion to
the thermoelectric converting portion 1.
(B) Since direct current flows in the direction of stacking of the
thermoelectric elements 1p, 1n, since the cross sectional areas of
the electrodes 11, 12 across the direction of the current are
relatively large, and since the flowing distance of current is a
thickness of the electrodes 11, 12, the loss of electricity due to
the electric resistance and the amount of the Joule heat are both
reduced.
Since any two of the adjacent endothermic electrodes 11 or of the
radiative electrodes 12 which have different voltage are not
disposed on the same insulating member as in the conventional
device shown in FIG. 27, the electric insulation is easily achieved
even though the size of the device becomes small.
(C) Since the endothermic electrodes 11 and the radiative
electrodes 12 absorb and radiate heat at both surfaces thereof, the
surface areas of electrodes 11, 12 required to absorb and radiate
the heat sufficiently becomes half as compared with the
conventional device which radiate and absorb the heat at just one
surface of the electrodes.
(D) Insulating members are not required between the thermoelectric
elements and the electrodes 11, 12 as in the conventional device
shown in FIG. 27. There is no worry about the heat resistance due
to the insulating members.
(E) In the conventional device shown in FIG. 27, each
thermoelectric element 1p', 1n' is aligned on the flat surfaces of
the insulating plates 85, 87. If the widths of the thermoelectric
element 1n', 1p' are not even, it is difficult to contact the
thermoelectric elements 1n', 1p' with the insulating plates 85, 87.
The present invention does not have such a problem.
Other modifications of the electrodes 11, 12 can be applied. For
instance, the electrodes 11, 12 can have fins instead of louvers
22. A heat pipe can be formed by the electrodes 11, 12 or a heat
pipe can be provided to the electrodes 11, 12. FIGS. 3 through 7
show these modifications of the electrodes 11, 12.
FIG. 3 shows one of the modifications of electrodes 11, 12 wherein
each of the endothermic electrodes 11 and each of the radiative
electrodes 12 form the heat pipe thereby. Each electrode 11, 12 has
a pair of rectangular metal plates 25, 26 which are joined by
soldering the peripheries thereof. These metal plates 25, 26 have
flat surfaces or tongues at their one end where the thermoelectric
elements 1n, 1p are connected and a concaved portion 27 at the
other end and center portion thereof. Two concaved portions 27
confront each other to form a closed space 28 which has a flat
cross sectional shape and into which refrigerant, fluorocarbon R21,
is introduced. The refrigerant evaporates at one end of the closed
space 28 which is further from the thermoelectric converting
portion 1 (e.g., at the top end of electrode 11 in FIG. 3) and then
the evaporated refrigerant is liquefied at the other end of the
closed space 28 which is closer to the thermoelectric converting
portion 1. The liquefied refrigerant flows back to the end by a
capillary phenomenon. These operations are carried out repeatedly
as a heat pipe, and the heat transfer capacity is increased by
utilizing a latent heat of the refrigerant.
FIG. 4 shows another modification of the electrodes 11, 12 wherein
the electrodes 11, 12 are made of copper alloy and have U-shape.
The electrodes 11, 12 are bent into a U-shape at the center portion
in such a manner that a free end thereof comes close to the
thermoelectric element 7.
FIG. 5 shows a further modification of the electrodes 11, 12
wherein the electrodes 11, 12 comprise a flat plate 35 and a bent
plate 36. The bent plate 36 is disposed between two adjacent flat
plates 35 in parallel.
To avoid contact of adjacent electrodes 11, 12, it is useful to
provide a spacer (not shown) made from nonconductive material
between electrodes 11, 12 or provide a nonconductive coating on the
heat exchanging portion of the electrodes 11, 12. Even if the heat
exchanging portion is deformed, the electric insulation is achieved
well.
FIG. 6 shows still another modification of electrodes 11, 12
wherein corrugated fins made from copper are disposed between
adjacent electrodes 11, 12. The electric insulating plates 30 are
also provided on one surface of the electrodes 11, 12.
When the electrodes 11, 12 are made from aluminum, aluminum layers
can be applied on the electrodes 11, 12 instead of the electric
insulating plate 30.
FIGS. 28 and 29 show a modification of the corrugated fins.
Corrugated fins 31 include a copper layer 31a, a copper layer 31b
and a nonconductive resin layer 31c which is held by the copper
layer 31a and the copper layer 31b. The copper layers 31a, 31b and
the resin layer 31c are elastic and are combined by an adhesive.
The corrugated fins 31 have louvers 31d thereon and are attached to
the adjacent electrodes 11, 12 by soldering or brazing on both
sides. Therefore, the mechanical strength of the corrugated fins 31
and the electrodes 11, 12 is increased and the heat transfer
efficiency increases.
The fins 31 can be made from aluminum alloy instead of copper
alloy.
THE SECOND EMBODIMENT
The second embodiment of the present invention is now described.
FIG. 7 is a cross sectional view of the second embodiment and FIG.
8 is a cross sectional view taken along the line 8--8 of FIG.
7.
The thermoelectric converting portion 1 comprises the N-type
thermoelectric element 1n, the endothermic electrodes 11, the
P-type thermoelectric elements 1p and the radiative electrodes 12
all of which are disposed in a cylindrical duct 5. The duct 5 has a
central partition 50 on an axis thereof which divides an inner
space of the duct 5 into a radiative fluid passage 51 and an
endothermic fluid passage 52. The central partition 50 has a
rectangular opening 53 into which the thermoelectric converting
portion 1 is disposed. The longitudinal axis of the thermoelectric
converting portion 1 is coincident with the axis of the duct 5.
Each of the electrodes 11, 12 has a square contacting portion 20 to
which the N-type thermoelectric elements 1n and the P-type
thermoelectric elements lp are in contact and a fan-shaped heat
exchanging portion 21 which elongates from a side of the square
contacting portion 20 and is made from copper. A plurality of
openings 59 are formed radially with respect to the contacting
portion 20 in the heat exchanging portion 21 of the endothermic
electrode 11 and a fluid to be cooled can flow through the openings
59 in the duct 5. The radiative electrode 12 has the same fan shape
as that of the endothermic electrode 11 but are headed in the
opposite direction to the endothermic electrode 11.
According to this embodiment, since the central partition 50
supports the thermoelectric converting portion 1, the supporting
structure becomes simple and does not interfere with heat
transfer.
FIG. 9 shows an air conditioner for an automobile to which the
second embodiment is applied. A fan 6 is provided upperstream of
the duct 5 and the thermoelectric converter of the present
embodiment is provided downstream of the duct 5. The duct 5 has a
common intake 56, a cooled air outlet 57 and a warmed air outlet
58.
Fresh-air or a air from inside the automobile is introduced into
the duct 5 through the common intake 56 by the fan 6. The air
cooled by the endothermic electrodes 11 and the air warmed by the
radiative electrode 12 are mixed by controlled valves (not shown)
together in a desired proportion and the mixed air is introduced
into the automobile.
A plurality of thermoelectric element 1p, 1n can be attached to
each of electrodes 11, 12.
THE THIRD EMBODIMENT
The third embodiment of the present invention is described in FIGS.
10 through FIGS. 12. FIG. 11 is a front view with parts broken
away. Four thermoelectric converting portions 1a through 1d are
built up vertically against the longitudinal axis thereof and are
provided in a case 9 made from nonconductive resin. Each of the
thermoelectric converting portion la through 1d include the N-type
thermoelectric elements 1n, the endothermic electrodes 11, the
P-type thermoelectric elements 1p and the radiative electrodes
12.
Each electrode 11, 12 is comb-shaped as shown in FIG. 12. The
N-type thermoelectric element 1n and the P-type thermoelectric
element 1p are attached to base portions 11a, 12a of the electrodes
11, 12 by soldering in such a manner that the N-type and P-type
thermoelectric elements 1n and 1p are in a line. The endothermic
electrodes 11 and the radiative electrodes 12 are headed in
opposite directions relative to each other.
One end of each radiative electrode 12 of the thermoelectric
converting portion 1a which is located at the bottom is in contact
with a bottom plate 9a of the case 9. One end of each endothermic
electrode 11 confronts one end of a respective endothermic
electrode 11 of the thermoelectric converting portion 1b which is
located next to the converting portion 1a. One end of each
radiative electrode 12 of the thermoelectric converting portion 1b
confronts one end of a respective radiative electrode 12 of the
thermoelectric converting portion 1c. One end of each endothermic
electrode 11 of the thermoelectric converting portion 1c confronts
one end of a respective endothermic electrode 11 of the
thermoelectric converting portion 1d. One end of each radiative
electrode 12 of the thermoelectric converting portion 1d which is
located the furthest up is attached to an upper plate 9c of the
case 9.
Partition plates (not shown) are disposed in the case 9
perpendicularly to the sheet of drawing for FIG. 11 in such a
manner that the inner space of the case 9 is divided into a first
radiative passage 91, a second radiative passage 93, a third
radiative passage 95, a first endothermic passage 92 and a second
endothermic passage 94. The radiative electrodes 12 are located in
each of the radiative passages 91, 93, 95 and the endothermic
electrodes 11 are located in each of the endothermic passages 92,
94. Especially, two rows of the radiative electrodes 12, 12 of the
thermoelectric converting portion 1b, 1c are located in the second
radiative passage 93. Similarly, in the first and the second
endothermic passage 92, 94, two rows of the endothermic electrodes
11 are located respectively.
The direction of air flowing through each radiative passages 91,
93, 95 is perpendicular to the sheet of drawing for FIG. 11. Air
flowing through each endothermic passage 92, 94 flows from left to
right in FIG. 11. Front plates 9e and a rear plates (not shown) are
disposed at front and rear ends of the endothermic passages 92, 94
to close both ends, and side plates 9e, 9d are disposed at both
sides of the radiative passages 91, 93, 95 to close both sides.
A supporting plate 9g is attached to both of the front plates 9e,
9e and a similar shaped supporting plate (not shown) is attached to
both of the rear plates. The whole thermoelectric converter
including case 9 is fixed in a duct 5a (shown in FIG. 10).
FIG. 10 shows an air conditioner for an automobile to which this
embodiment is applied. The thermoelectric converter is located
downstream of the duct 5a and a fan 6a is located upstream of the
duct 5a. The air pulled in by the fan 6a is divided into two
streams which cross vertically of each other and are introduced
into a warmed air duct 5b and a cooled air duct 5c through the
radiative passages 91, 93, 95 and the endothermic passages 92, 94
respectively. According to the present embodiment, since the
radiative and the endothermic passages 91, 93, 95 and 92, 94 cross
each other perpendicularly, the warmed air and the cooled air are
easily separated. The same kind of electrodes located in the same
passage can be combined. For example, the endothermic electrodes 11
of converting portion 1a and those of converting portion 1b are
both in passage 92, and each set of two opposing electrodes 11 in
that passage can be combined into one continuous electrode. The
same can be done in passages 93 and 94.
FIGS. 13 and 14 show a modification of the thermoelectric
converting portion useable in any of the embodiments disclosed
above and below. The endothermic electrodes 11 and the radiative
electrodes 12 are inclined 45.degree. relative to the direction C
(shown in FIG. 11 as well as FIGS. 13 and 14) in which the N-type
thermoelectric element 1n and the P-type thermoelectric elements 1p
are lined. Thermal nonconductive plates 99 are disposed between two
adjacent endothermic electrodes 11 and two adjacent radiative
electrodes 12 respectively to make a warmed air passage and a
cooled air passage.
Each radiative electrode 12 has rectangular openings 96 and guide
louvers 96a at edges of the openings 96. Each endothermic electrode
11 has rectangular openings (not shown) and guide louvers 95a at
edges of the openings. The louvers 95a are parallel to the
direction C and the louvers 96a are perpendicular to the direction
C. The louvers 95a, 96a are made by bending strips to make
openings. The cooled air passing through the endothermic electrodes
11 flows parallel to the direction C and the warmed air passing
through the radiative electrodes 12 flows perpendicularly to the
direction C. Cooled air exits the right end in FIG. 13 and warmed
air exits the bottom side.
FIG. 15 shows a modification of the endothermic electrode 11. The
endothermic electrodes 11 have a plurality of strips 110 extending
from a base portion 111 to which thermoelectric elements 1p, 1n are
attached. Adjacent strips are bent in opposite directions,
continuously and symmetrically with respect to the base portion
111. The direction of air passing through the endothermic electrode
11 is not restricted.
THE FOURTH EMBODIMENT
The fourth embodiment of the present invention is described with
regard to FIGS. 16 through 20. In FIG. 16, all electrodes 11, 12
have louvers 22 thereon, however, the louvers 22 are shown on just
one electrode 11 for convenience. In FIGS. 16 and 20, central
portions of the device are not shown.
In FIG. 16, from right to left, an endothermic electrode 11, a
spacer 17, a spacer 16, a radiative electrode 12, a spacer 17, a
spacer 18, an endothermic electrode 11, a spacer 17, a spacer 16, a
radiative electrode 12, a spacer 17, a spacer 18, a endothermic
electrode 11 and so on are built up sequentially. The spacers 16,
17 and 18 are made of nonconductive resin material. The endothermic
electrodes 11 and the radiative electrodes 12 are aligned in two
rows.
At one end of the thermoelectric converter 1, a terminal 13 is
disposed at the head of one row of electrodes 11, 12, while the
head of the other row has a terminal 14. At the other end of the
thermoelectric converter 1 is an electrode plate 15 which connects
one row with another row of the electrodes 11, 12. These elements
described above are tightened by two bolts 41a, 41b.
In FIG. 17, the electrodes 11, 12 have holes 11a, 12a into which
the bolts 41a, 41b are inserted. The spacers 16, 17, 18 have holes
16a, 17a, 18a, 16b, 17b, 18b into which the bolts 41a, 41b are
inserted. The terminal 13, 14 and terminal plate 15 have holes 13a,
14a, 15a, 15b into which the bolts 41a, 41b are inserted.
Nonconductive collars 42 are disposed between the bolts 41a, 41b
and the terminals 13 14 and between the nuts 41c, 41d and the
terminal plate 15. As shown in FIG. 19 and FIG. 20, the N-type
thermoelectric element 1n or the P-type thermoelectric element 1p
is disposed between the endothermic electrode 11 and the radiative
electrode 12.
The spacers 16, 17, 18 have holes 16c, 16d, 16e, 16f, 17c, 17d,
17e, 17f, 18c, 18d, 18e, 18f in which the N-type thermoelectric
element 1n or the P-type thermoelectric element 1p is disposed.
A voltage is applied to the positive and negative terminals 13, 14
in FIG. 20. Current flows from the terminal 13 in parallel through
two rows of the P-type and N-type thermoelectric elements, which
are on opposite sides of bolt 41a, to plate 15. Plate 15 carries
the current to the right side where it flows in parallel through
another two rows of the P-type and N-type thermoelectric elements,
which are on opposite sides of bolt 41b, to terminal 14. The
endothermic electrodes 11 absorb the heat and the radiative
electrode 12 radiates the heat.
The way of assembling the thermoelectric converter 1 is described
hereinafter.
A solder coating is formed on surfaces of the electrodes 11, 12
which contact the thermoelectric elements 1p, 1n. The electrodes
11, 12, the spacers 16, 17, 18, the thermoelectric elements 1p, 1n,
the terminals 13, 14, 15 and the collars 42 are built up
sequentially and are tied by the bolts 41a, 41b and the nuts 41/c,
41d. The assembled thermoelectric converter 1 is heated to about
180.degree. C. to melt the solder coating on the electrodes 11, 12
and then cooled down to solidify the melted solder and fix the
thermoelectric elements 1p, 1n to the electrode 11, 12.
The spacers 16, 17, 18 made from elastic resin make the electrodes
11, 12 contact the thermoelectric elements 1p, 1n firmly by an
elasticity thereof. Adhesive can be applied on the surfaces of the
spacers 16, 17, 18 to bond them firmly. The choice of adhesive must
be such that the adhesive will not cure during the soldering
operation even if the temperature is under 180.degree. C. After the
soldering operation the adhesive is cured by lowering the
temperature suitably.
Since two rows of the thermoelectric elements 1p, 1n are provided
to one row of electrodes 11, 12, the number of thermoelectric
elements is increased (doubled) and a large amount of heat transfer
is achieved.
The spacers 16, 17, 18 insulate the radiative electrodes 12 from
the endothermic electrodes 11 thermally and electrically. The high
mechanical strength of the thermoelectric converter is achieved by
the spacers 16, 17, 18 because the spacers 16, 17, 18 combine two
rows of the electrodes.
The spacers 16, 18 are L-shaped in cross section as shown in FIG.
18. The spacers 16 cover the end of the radiative electrodes 12 and
the spacers 18 cover the end of the endothermic electrodes 11 in
order to prevent short circuit between the radiative electrode 12
and the endothermic electrode 11 due to condensed water when the
thermoelectric converter is used for cooling or drying air.
FIG. 21 shows a holder 45 for holding the electrodes 11, 12 to
prevent them from deforming. The holder 45 has slots 451 the number
of which corresponds to the number of the endothermic electrodes 11
or the radiative electrode 12 and into which each electrode is
inserted respectively. The holder 45 keeps the interval of adjacent
electrodes and prevents a short circuit due to the deforming of the
electrodes.
FIGS. 22 and 23 show that the endothermic electrode 11 is molded in
a resin spacer 19. The thermoelectric elements 1p, 1n are soldered
to one surface of the endothermic electrode 11 which have louvers
22. The radiative electrode 12 is also molded in a resin spacer 19.
According to this structure, the electrodes 11, 12 can be easily
assembled to the spacer 19, and the clearance between the spacer 19
and the electrodes 11, 12 become small. The electrodes 11, 12
expand and contract due to heat radiation and absorption and the
thermoelectric elements 1p, 1n are fixed on the electrodes 11, 12
by soldering, so that some stress arises at the contacting surfaces
of the thermoelectric elements 1p, 1n and the electrodes 11, 12.
The electrode 11 shown in FIG. 30 has a slit 11b in a center
portion thereof to absorb expansion and contraction and reduce
stress. The electrode 11 shown in FIG. 31 has two slits 11c, 11d at
both sides of the hole 11a for the same purpose.
THE FIFTH EMBODIMENT
FIGS. 24 through 26 show the fifth embodiment of the present
invention. The electrodes 11, 12 are bent zigzag and the P-type
thermoelectric element 1p and the N-type thermoelectric element 1n
are attached thereto. Spacers 200 are disposed between the P-type
thermoelectric element 1p and the N-type thermoelectric element 1n
to insulate therebetween thermally and electrically. All of the
thermoelectric elements 1p, 1n are connected in parallel.
The invention is not to be limited to the foregoing since further
variations in the invention will become apparent to those skilled
in the art and such are to be included in accordance with the scope
of this invention as defined by the following claims.
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